Self-regulating arc-lamp.



M. H. BAKER.

SELF EEGULATING ARC LAMP.

APPLIOATION IILED AUG. 1, 1903.

Patented Sept. 6, 1910-.

Wz'z'n esses:

MALCOLM BAKER, OFNEW YORK, N. Y.,

AND mannracrnnme COMPANY, A

ASSIGNOR T0 WESTINGHOUSE ELECTRIC CORPORATION OF PENNSYLVANIA.

SELF-REGULATING ARC-LAMP.

Specification of Letters Patent.

Patented Sept. 6, 1910.

Application filed August 1, 1903. Serial- No. 167,847.

characteristics.

It is well known that, in the operation of an ordinary arc lamp wherein the arc is formed between the points of electrodes in alinement with each other, the voltage of the arc varies in inverse ratio to the current. For this reason, any changes of electrical conditions at the arc introduce disturbances of the circuit conditions generally, and such disturbances have to be guarded against by external means of regulation and control.

()ne of the objects of the present invention is to make the electric arc self-regulating by providing such paths for the current leading to the terminals of the are that the lines of force due to the current in the said paths acting upon the lines of force generated by the current in the arc itself will tend by mutual repulsion to make the voltage of the arc vary in direct ratio to the current. This is done by so relating the direction of flow of the current to the arc terminals that the lines of force due to the current will tend to fan out the are, and as the lines of force increase in direct proportion to the strength of the Current, such an arrangement will cause the arc to be fanned out still further by an increase of current, whereby the desired condition is attained. In other words, an increase of current will be followedby an increase of voltage at the arc and vice Versa. In this way, the arcitself becomes the regulator for the lamp circuit; that is to say, the entire control and regulationof the said circuit are localized in the arc. Besides rendering unnecessary the usual external regulating devices, the described property of the self-regulating arc makes it possible-to dispense with all magnetic or other artificial means 'for spreading the electric are, as when the arc itself is designed to be used as the main source of illumination.

As a convenient means for conducting the electric current to the arc terminals in a manner suited to produce the effects described, I may make use of parallel electrodes, and I generally prefer to establish the are at the bottom of a pair of vertical electrodes arranged parallel to each other. Such an arrangement provides for the even burning away of the electrodes at their lower ends and renders it unnecessary to provide any feeding mechanism, inasmuch as, when the electrodes are parallel, their ends will remain the same distance apart.

My invention will-be understood by reference to the accompanying drawings, in which Figure 1 illustrates a lamp having electrodes in the shape of two concentric cylinders; and Fig. 2 is a bottom view of the lamp shown in Fig. 1.

In the drawings, 3 and 4 are the cylinder electrodes suitably mounted in holders, 13 and, 14,- the said holders being rigidly attached to a bed plate, 15, of some suitable insulating substance. The electrodes are surrounded by a conical chamber, 5, to protect the are from air drafts. In order to establish the are, an'igniter, 16, of metal or carbon, is pivoted to a metal strip, 17, to swing loosely at one end of a lever, 18. Thls lever 18 is pivoted to a support, 19, mounted upon'the bed plate, 15, and carries at lts upper end a counterweight, 20, so arranged as to hold the igniter 16 in contact with the electrode 4 when the lamp is out of operation. A small starting magnet, 21, is surrounded, by an iron clad shield, 22, and 1s mounted on a' bracket, 23, by means of a screw, 24. This bracket is attached to the bed plate 15 by means of a screw, 25, working 1n a slot in the bracket so that the position of the magnet 21 with relation to, the lever 18 may be altered at will. This is necessary in order to permit the proper setting of the igniter.

When the current is thrown upon the lamp, the core, 26, of the magnet, 21, is magnetized and attracts an armature, 27 fixed upon the lever 18, thus moving the said lever and establishing the are by drawing the -ignitcr 18 across the gap between the electrodes. The electrode 3 is fitted with a slot through whichthe igniter 16 travels. The are is thus established and then travels down until it reaches the lower ends of the electrodes where it fans out to shape as repre sented at 6.

It is important to iron clad the magnet 21 l in order to prevent magnetic leakage, which 1 would afiect the arc and'disturb' its even;

burning and proper action.

WVhen I emplo cyli drical electrodes, as

shown, I prefer to use the outer "cylinder as the positive electrode on direct current circuits and the inner cylinder as the negative electrode. Under the assumption that the electrodes are of equal thickness, the larger volume of the outer electrode will compensate for its more rapid consumption when it is used as the positive.

In employing cylindrical electrodes, on

alternating current circuits it will be found advantageous to construct the outer cylinder so that it shall have a proper fractional part of the thickness of the inner cylinder. I

lent to the deviceembodied in the iron shiel 1 described.

It is manifest that the electric arc, arranged under the described conditions, will be self-regulating, not only in multiple circuits but in series circuits aswell. Should the arc length in a' series lamp become shortened for any reason, the inter-acting lines of force would bebrought into closer relation, would exercise a greater mutual repulsion and the arc would'tend to resume its original length. On the other band, should the arc become lengthened, the current strength being constant and the interacting lines of force being morewidely se arated, the arc would tend to shorten itsel and tend to resume its original length.

I claim as my invention In an arc lamp a paratus, the combination with a pair 0 cylindrical electrodes, located the one within the other, of an igniter ;located at a point remote from the arcing ends of the electrodes.

Signed at New York, in the county of New York, and State of New York, this 16th, day of June, A. D. 1903.

MALCOLM H. BAKER.

Witnesses:

WM. H. CAPEL, GEORGE H. S'rooKBRmeE. 

